The use of mechanized systems to control the dispensing of ingredients in cup beverage vendors is an art recognized concept. For example, a typical approach utilizes a timing motor having an output shaft with a plurality of cams attached thereto. Rotation of the motor shaft thusly causes the cams to operate on switches which control solenoid valves and/or operate dry ingredient dispensing motors. Accordingly, the quantity of materials dispensed is at least partly determined by the dwell of the cams and the angular rotational speed thereof.
Mechanical control systems, when used for ingredient dispensing, are often inaccurate and difficult to adjust to achieve proper metering of the dispensed materials. For example, the length of a cam shaft (and therefore the number of cams) is limited since excessive shaft lengths tend to warp and to introduce error into the control system. Also, after a period of extensive use, the attendant wear introduces additional error into the system. Further, while the accurate adjustment of cam dwell angles is difficult, even under the best conditions, accessibility for manual adjustment of the cams is frequently very restricted due to the cam box size and typical location within cup beverage vending machines.
The subject invention provides for electronic control of the quantity of ingredients dispensed during the operation of the vending machine. When a coin operated relay switch and any one of several beverage selection switches are actuated, an associated circuit means latches in a circuit corresponding to the selected ingredient. A ramp generator operates in conjunction with a lapsed time voltage comparator circuit to activate an appropriate valve and/or ingredient dispensing motor when the compared voltage reaches a first preselected value and to later turn off the solenoid or dispensing motor when a second predetermined voltage is reached. An adjustable volume control resistive element is provided to permit the second voltage level to be varied thereby permitting the quantity of ingredients to be likewise varied.
A primary object of the invention is to provide a unique and improved method and electronic device for controlling ingredient dispensing in a cup beverage vending machine.
Another object of the invention is to provide a method and electronic device of the character described which is compact in size yet with which easy to effect ingredient volume control adjustments are possible both during the initial manufacturing of the vending machine and after said machine is operational and in the field.
Another object of the invention is to provide a method and device of the character described immediately above which includes a unique circuit means, in the vending machine environment, having an easily accessible and manipulated control mechanism for metering out desired quantities of ingredients. It is a feature of the invention that the combined circuit means and control mechanism easily lends itself to calibration thereby further simplifying the control over the vended or dispensed product.
A still further object of the invention is to provide, in a vending machine of the character described, a unique circuit means and control mechanism of increased reliability which greatly reduces the need for the service and maintenance heretofore common with ingredient dispensing vending machines using mechanical timing cam devices. It is an important feature of the subject invention that rapid initial adjustments of a plurality of ingredient dispensing mechanisms may be made over virtually a complete timing cycle. Known prior art timing devices and systems which use motor shafts with associated cams are not only subject to wear, warpage and adjustment difficulties but generally had a maximum 180.degree. dwell time for the dispensing operation. The subject invention now permits the dispensing of ingredients over virtually a complete timing cycle and concurrently eliminates the above stated difficulties.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.